CO2 Capture and H2 Production: Assessment of Two Key Components for Synthetic Renewable Fuels

Abstract

The transition toward a carbon-neutral society requires reshaping the world’s energy system. But even a world with net-zero emissions will depend on hydrocarbon fuels (but not necessarily of fossil origin), e.g., in the chemical industry or transport sector. While this requires the sequestration of CO2 from large point sources combined with storage and the application of negative emission technologies, the transition can be accelerated by implementing so-called power-to-X (PtX) technology. This technology makes it possible to convert power, in the form of renewable energy, into fuels (X) efficiently. PtX is an interesting option for the harder-to-abate sectors like aviation, maritime shipping, and the chemical industry. One possibility is using solar energy as the power source, combined with two abundant reactants, i.e., H2O and CO2, to produce carbon-neutral fuels. While technological pathways already exist to supply the two initial components, i.e., capturing CO2 from fossil power plants or the ambient air and water splitting to produce H2, the uncertainties are high regarding technical performance and economic feasibility. Therefore, the research reported in this thesis addresses the capturing and sourcing of these two critical components for producing solar hydrocarbon fuels: i) carbon dioxide obtained from the air and ii) renewable hydrogen produced from water using solar energy. The aim is to assess different routes for the supply of CO2 and H2 in terms of technological and economic performance and to identify the key challenges for bringing down the costs.